Glaciers covered much of North America during the Pleistocene Epoch that began nearly two million years ago and lasted until about 10,000 years ago. Glaciers did not move over what is now West Virginia, but did dramatically affect the drainage pattern.

Prior to the Pleistocene the Monongahela River flowed northwestward by way of present Beaver and Grand rivers, in Pennsylvania and Ohio, to the preglacial St. Lawrence River, and the preglacial Teays River crossed central Appalachia via present New River to present Nitro and then followed the Teays Valley, exiting the state at present Huntington. When the Wisconsin Glacier became stationary along a line beginning in Ohio about 10 miles north of the top of the present Northern Panhandle of West Virginia and running southwestward to near Maysville, Kentucky, on the Ohio River, the preglacial routes of the Monongahela and New-Teays rivers were blocked by the ice front, forming ancient Lake Monongahela and Lake Tight (also known as Teays Lake). As the impounded water rose above divides leading to other basins, the modern Ohio River was pieced together in a continuous stream along the forward edge of the glacier, and the waters of the Monongahela and Ohio rivers were joined over the course between New Martinsville and St. Marys.

The Teays Valley between Nitro and Huntington is an interesting glacial relic. The lake of the Teays extended from Chillicothe, Ohio, to near Hawks Nest, and during its 25,000 years of existence was filled with lake clay and alluvial silt deposits. After the lake drained as a result of later changes, the Teays River was diverted probably through stream piracy by the Kanawha River to Point Pleasant where it joined the recently created Ohio River. The Teays Valley, currently drained by Hurricane Creek and Mud River, has in modern times become a major highway and rail transportation artery and a residential, commercial, and industrial region between Huntington and Charleston.